Generally, a neutral-point-clamped (NPC) DAC can be applied to distributed energy or renewable energy and can convert DC power into usable AC power. Because the power stage of the NPC DAC supplied with a high DC input voltage can employ low-voltage switching devices, the power loss of the switching devices can be reduced. Moreover, the NPC DAC has a low electromagnetic interference (EMI) and a low voltage harmonic distortion. Therefore, the NPC DAC has been widely applied to renewable power converter products recently.
The NPC DAC supplied with a high DC input voltage converts DC power into AC power by turning on or off switching devices, and malfunctions or noises may occur on the switching devices because the switching devices are being switched. This will cause short circuits in the DC end which will damage the switching devices.